Question

The maximum number of jets generally employed in an impulse turbine without jet interference are
A. \[6\]
B. \[5\]
C. \[7\]
D. \[8\]

Answer 1

Hint: First of all, we need to analyze jet velocity and energy of a turbine.
After that we will obtain the required answer. The Pelton water wheel is an example of an impulse turbine.

Complete answer:
If we equate the equation of initial jet velocity and energy of a turbine, then we will get a minimum number of jets to be\[6\]. So, the maximum number of jets generally employed in an impulse turbine without jet interference are \[6\].
In a model runner for a \[6\] -nozzle Pelton turbine, jet interference in buckets and jet disturbance outside of buckets were visually observed. The visual observation revealed that the jet from the first nozzle that entered the splitter into a bucket and is now going to discharge at the outcut of the bucket is interfered with by the jet from the second nozzle that just entered the outcut of the same bucket.

So, the correct answer is “Option A”.

Additional Information:
Impulse turbine: An impulse turbine is a turbine that is powered from a nozzle by high-speed water jets or steam guided at vanes or buckets connected to a wheel. The resulting impulse spins the turbine and extracts kinetic energy from the fluid flow (as defined by Newton's second law of motion).

Note:
 It is important to remember that typically, an impulse turbine’s blades are bucket-shaped so that they capture the fluid and steer it off at an angle or sometimes even back the way it came.
(because that gives the fluid to the turbine the most effective transfer of energy).